pH-sensitive polymeric nanoparticles for co-delivery of doxorubicin and curcumin to treat cancer via enhanced pro-apoptotic and anti-angiogenic activities

Co-delivery of multiple drugs with complementary anticancer mechanisms by nano-carriers offers an effective strategy to treat cancer. The combination of drugs with pro-apoptotic and anti-angiogenic activities is potentially effective in treating human hepatocellular carcinoma (HCC). Herein, we developed a co-delivery system for doxorubicin (Dox), a pro-apoptotic drug, and curcumin (Cur), a potent drug for antiangiogenesis, in pH-sensitive nanoparticles (NPs) constituted with amphiphilic poly(β-amino ester) copolymer. Dox & Cur co-loaded NPs ((D + C)/NPs) were prepared with optimized drug ratio, showing low polydispersity, high encapsulation efficiency, and enhanced release in the acidic environment of cancer cells. Furthermore, enhanced cellular internalization of cargoes delivered from (D + C)/NPs were observed in human liver cancer SMMC 7721 cells and human umbilical vein endothelial cells (HUVECs) compared to the use of free drugs. The (D + C)/NPs induced a high rate of apoptosis in SMMC 7721 cells through decreased mitochondrial membrane potential. Additionally, (D + C)/NPs exhibited stronger anti-angiogenic effects including inhibition of HUVEC proliferation, migration, invasion, and tube formation mediated VEGF pathway modulation in vitro and in vivo. Taken together, encapsulation of the pro-apoptotic drug Dox and antiangiogenic agent Cur in pH-sensitive NPs provides a promising strategy to effectively inhibit HCC progression in a synergistic manner. The combination of multiple drugs has been demonstrated to be more effective than single treatment. However, the different physicochemical and pharmacokinetic profiles of each drug render optimal delivery challenging. In view of the great delivery advantage of nanocarriers to unify the multiple drugs in vivo, stimulus-responsive nano-carriers are more crucial to increase efficacy and reduce toxicity from off-target exposure. Therefore, herein the pH-sensitive nanoparticles, composed by d-α-tocopheryl polyethylene glycol 1000-block-poly (β-amino ester) (TPGS-PAE) polymers, have been fabricated for doxorubicin (Dox) and curcumin (Cur) co-delivery, which exhibited diverse anticancer approaches, i.e. pro-apoptosis and antiangiogenesis. The precise intracellular target site and effective drug combination concentration result in the enhanced antitumor efficiency and the reduced systematic toxicity of Dox. The co-encapsulation of the pro-apoptotic drug and antiangiogenic agent in pH-sensitive NPs provides a promising strategy to effectively inhibit malignant neoplasm progression in a synergistic manner.